1. Field of the Invention
The present invention generally relates to a photosensitive medium and, more particularly, to the photosensitive medium having a surface protecting layer.
2. Description of the Prior Art
An organic photosensitive medium comprising an organic photoconductive material mixed with a binding resin is today widely employed. As compared with the photosensitive medium comprising selenium or cadmium sulfide, the organic photosensitive medium has advantages in that it poses no substantial hygienic problem and in that it can be manufactured on an industrial scale.
However, the organic photosensitive medium is low in hardness and does therefore tend to pose a problem in that, as a result of the repeated frictional contact with transfer papers, cleaning members, developing material and others, the photosensitive medium is apt to wear and/or be scratched.
To alleviate tha above discussed problem, a technique has been proposed to provide the organic photosensitive medium with a surface protective layer of high hardness. While amorphous hydrocarbon is known as a material for the surface protective layer having a high hardness, a mere formation of the surface protective layer, in the form of a film of amorphous hydrocarbon, on the organic photosensitive layer does not allow the organic photosensitive medium to exhibit a sufficient adhesive property and a durability and, therefore. the surface protective layer is apt to be peeled off from the organic photosensitive layer when repeatedly used for a substantial period of time.
Also, the film of amorphous hydrocarbon forming the surface protective layer is susceptible to deterioration in the presence of ozone and, therefore, when a copying is made under a high humidity environment, an image reproduced on a transfer paper tends to be blurred.